problem with histogram example

I'm using gnuplot 4.2.3. I wanted to learn how to plot histograms and
tried the example provided in the do***entation but I get an error:

gnuplot> set style histogram errorbars gap 2 lt -1 lw 2
                                             ^
         ';' expected

The set style command is copied verbatim from the gnuplot
do***entation. Any ideas? If anyone isn't using monospace fonts, the
location of the error as pointed to by the ^ is just below 'lt'.

Cheers,
/ALiX